No other details were given in Thursday’s report by the semi-official ISNA news agency. It also remains unclear why authorities targeted the liberal-minded diplomat, Bagher Asadi, and whether it could be related to next month’s presidential election.

Foreign Minister Ali Akbar Salehi is quoted as defending the integrity of Asadi, who previously held a senior position at Iran’s U.N. mission. Asadi also is a close ally of former pro-reform President Mohammad Khatami.

The report did not say when Asadi was detained.

Elections are planned June 14 to pick a successor for President Mahmoud Ahmadinejad.